Research Roundup: Valine Restriction | Microbes | Iron in the Brain

Three recent studies on longevity and healthspan

The “Longevity Research Roundup” is a feature for paid subscribers of Longevity Lifehacks. Every week or two, I will bring you a quick summary of new research studies that I think are important — and actionable — in the fields of longevity, lifespan, or healthspan.

Study #1: Lifelong restriction of dietary valine has sex-specific benefits for health and lifespan in mice

This preprint caught my attention because it again shows that different amino acids have different effects on longevity (see my recent article on proline reversing mitochondrial dysfunction in aging). There’s often a mental shortcut, in my mind anyway, that protein is good and amino acids = protein.

The researchers found that valine restriction improved metabolic health and promoted leanness in both male and female mice. It also reduced frailness in both sexes, but it only extended lifespan significantly (23%) in male mice.

Valine is one of the branched-chain amino acids (BCAAs), which are abundant in whey protein and chicken breast. BCAA supplements are popular with weight lifters. The other BCAAs include leucine and isoleucine.

It’s been known for a while that calorie restriction increases lifespan in most mammals, and that the reduction of BCAAs is one reason that calorie restriction increases lifespan. The other thing that research shows is that BCAAs play an integral role in insulin resistance in humans. This is shown through a number of genetic studies. (Genetic Lifehacks article explaining the genetic connections with BCAAs and IR.)

I still have a hard time wrapping my head around the conflicting studies and advice on dietary protein in aging. On the one hand, protein is needed for maintaining lean muscle and bone health. But there’s a clear trend in the research that shows that the BCAAs are likely not what we should be relying on for boosting protein intake in the context of longevity and metabolic health. (Not medical advice - I’m just explaining the research studies here.) According to the FDA database, foods that are high in valine that people actually eat include soy protein powder, whey protein powder, turkey, ham, pork shoulder, beef steak, and chicken breast.

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